The present invention relates generally to a method and a device for solvent cleaning of a fuel injection valve in a fuel injection system of an internal combustion engine. More particularly, the invention relates to a fuel injection valve cleaning method and device which is capable of cleaning up the fuel injection valve without taking it off from the engine cylinder block. The invention further relates to a cleaning agent applicable for the method and the device.
In a fuel injection internal combustion engine, gums, sludge and so on are apt to adhere on the fuel injection valve by using gasoline composing of a high rate of lead, surfur and so on and subjecting same to recirculated exhaust gas. The adhering gums, sludge and so on will narrow the fuel passage and result in a drop in engine performance. In order to maintain good engine performance high or to recover lost engine performance, it is necessary to clean up the gum, sludge and so on adhering to the fuel injection valve.
Conventionally, the fuel injection valve is replaced with a new one or previously cleaned one. In this procedure it is necessary to take out the fuel injection valve from the engine assembly. To take out the fuel injection valve, the fuel injection assembly including the fuel pipe, connector, harness and so on must be also taken out. Since the fuel injection assembly has a complicated structure and is difficult to be taken out, the disassembling operation itself is substantially difficult and takes a remarkably long time. Furthermore, the fuel injection valve as a replacement part is rather expensive and makes replacing the fuel injection valve quite expensive.